Goodness, Sparky. Just 20 years to get a diagnosis? Were you on the fast track or something? Took 'em 43 to get a clue about my BPD. So you and Northof have an abundance of "healthy happy living" to enjoy when your recovery work is paying off.
Northof, I'm an 18 year sourdough and the last 8 of those was a loyal Homerhoid. I'd trade to come back in a heartbeat. But there are limits on what helpers know and can do there. You may have to keep digging and count on your own research more than in most places. I'm sure that's one of the reasons mine went undiagnosed those 18 years. Nobody there knew what the heck BPD was!!!
As for whether or not the diagnosis "fits".. I'm of the school that says if it's broke, fix it and worry about the name later. If you have behavior patterns that are causing yourself and others pain, why not invest some work in developing behavior and thought patterns that result in far more healthy and happy days?
Have you read "256 shades of BPD" here? Very brief, with a nice link to the DSM criteria...
http://www.bpdrecovery.com/modules.php?name=Content&pa=showpage&pid=8l
My T and I went back and forth on whether or not my behavior pattens "fit" the diagnostic criteria for nearly a year. Finally I gave up and just put all my energy into doing the recovery work. It worked. Since then, I've learned that there can be some pretty subtle forms of the more dramatic behavior patterns we see in diagnostic literature. For example, the "pattern of unstable interpersonal relationships" can refer to many kinds of relationships, not just family. Work relationships, friends, church activities.. these are all places where that behavior pattern can come into play. Hell, you even see it in online groups.. certainly we see it here quite often, which should come as no surprise. That's also one of the reasons this is such a great place for learning and recovery. A wealth of all kinds of material,literally at our fingertips. Finally, BPD behavior patterns can be much more subtle than threatening to leave and name calling, while being every bit as hurtful.
So, I'm guessing that doing some work here can't hurt you any, and it could have some nice benefits. And as they yell up and down the river all day and night about now.... "fish on". Just drag that ol' 40 pounder up onto the gravel and get the smoker fired up.